Method of processing metals for use in alloying furnaces



United States Patent 3,484,289 METHOD OF PROCESSING'METALS FOR USE INALLOYING FURNACES. Alvin Wasserman, Detroit, Mich. (1521 Charrington,Birmingham, Mich. 48010) No Drawing. Filed Nov. 3, 1965, Ser. No.506,274

Int. Cl. B08b 5/00 US. Cl. 134-26 6 Claims ABSTRACT OF THE DISCLOSURE Ascrap recovery method in which unused scrap metal of odd-shapes butknown metallurgical composition is pro-shaped and pre-treated in suchfashion as to render them suitable for use as a constituent in qualityalloy melting furnaces by first cutting said unused" scrap metal intoparts of appropriate size, secondly, chemically cleaning the cut partsand thirdly, heat treating the out and cleaned parts to condition themfor shipment to the steel making plants.

This invention relates to a method of processing metal sheets so as tomake them useful as constituents, along with other metals, in meltingfurnaces which produce alloys; and more particularly to a method ofsizing and cleaning metals of known metallurgical composition to provideelements useful for such alloying furnaces.

Scrap steel which results from metal working processes is often of theproper metallurgy but improper physical configuration for use in othermetal working operations, and is normally bailed and delivered to steelmills for use as a constituent in the production of new steel in blastfurnaces. As such, it has a value not appreciably higher than used scrapwhich derives from the salvaging of obsolete or inoperative devices suchas automobiles, which have a large steel content. This metal workingscrap, at least in certain forms, such as sheets or slugs, would have amuch greater value if it could be employed in melting furnaces for theproduction of quality alloys. Use in this manner is normally preventedby the odd physical configuration of the material which makes itunsuitable for both shipment and use in melting furnaces havingrelatively small apertures and the contamination of the material by dirtand oxides.

It is therefore a broad object of the present invention to provide aprocess for operating upon scrap material.

from metal working operations, and sheet and plate scrap material inparticular, in order to render it useful as an input to alloyingfurnaces.

The scraps so processed must be of a known and uniform metallurgy. Scrapsteel having a low carbon content has a particularly high economic valueas it may be used as a base in making special alloy steels incompetition with low carbon steel sheet or plate produced by a mill andsold directly for this purpose.

As disclosed in the following description of a preferred embodiment ofmy inventive process, the scrap sheet or plate is first formed intosegments of a relatively uniform size, all having dimensions equal to orless than a maximum. In the preferred embodiment this is done by feedingsheets of the material into stamping presses which die cut the sheetsinto relatively small shapes, such as squares. The odd shape of thescrap part will often prevent the formation of segments having the shapeof the dies, but the segments formed will be no larger than the full diecut segments. These sized segments are collected and de livered,preferably by automatic means, to a processing device which first washesthe segments by tumbling them through streams of detergent solutions andthen dries the clean segments by subjecting them to a relatively hightemperature for a sufiicient time to completely evaporate the cleaningsolution and any other surface moisture. This naces which consists ofthe combination of first cutting the scrap into segments all havingmaximum outer dimensions; then washing the segments by tumbling themthrough detergent solutions, and finally subjecting the segments,immediately upon their removal from the washing apparatus, to anelevated temperature for a sufiicient length of time to remove allmoisture from their surface.

The sterilized segments formed by the above process provide the user ofthe melting furnace with a constituent which decreases the inclusions inthe output of the furnace, produces less slag and results in a longerrefractory life. The product is, therefore, directly competitive withalloying steels as produced directly by a mill.

Other objects, advantages and applications of the present invention willbe made apparent by the following detailed description of a preferredembodiment of the process.

The preferred embodiment of the process is capable of operating uponmetals of various configuration or metallurgy. A typical material willbe sheets of a steel such as SAE 1010 which has a carbon content of lessthan 10%.

The sheets or plates are then fed to a stamping press which employs adie that preferably cuts a two inch by two inch square configuration.The irregularly shaped workpiece may be manually fed into the die sothat a number of small, square segments are formed. On the edges of thesheet, the dies may not cut full squares, but all of the part out by thedie will have dimensions no larger than those of the die.

The segments thus formed are delivered to a washer where they aretumbled through jets or streams of a suitable liquid detergent of a highalkaline type commonly used for cleaning impurities from the surfaces ofmetals. The exact configuration of the washer and the length of time towhich the segments are exposed to the detergent s ream is dependent uponthe particular configuration of the washer and the degree to which theparticular scrap being processed is contaminated by dirt and oxides.

Immediately upon the removal of the: washed segments from the washingprocess, they are subjected to a blast of 450 F. degree air for a periodof two minutes. We have determined that if the air blast has atemperature of less than 300 F. degrees there is a tendency of thinoxide coating to form on the newly washed segments before the moistureis fully evaporated and/or vaporized. The atmosphere is continuously andrapidly ventilated during this time to remove all moisture. It has beenfound that this removes all surface moisture so that the segments willnot begin to oxidize unless later subjected to moisture or a moistatmosphere.

Following this treatment, the segments are in condi furnace comprising:forming the sheets into a plurality of small segments having apredetermined maximum dimension; washing the formed segments in adetergent solution; and, subjecting the Washed segments, immediatelyupon removal from the washing process, to an air blast at an elevatedtemperature of not less than 300 F., in a ventilated atmosphere, for asufficient time to vaporize all moisture on the surface of the segmentsand thereby prevent the formation of thin oxide coatings on the newlywashed segments.

2. The process of claim 1 wherein the segments are Washed by tumblingthem through streams of a detergent solution.

3. The process of claim 1 wherein the segments are subjected to thetemperature of at least 300 degrees F. for a period of at least twominutes.

4. In the process defined in claim 1, said blast of hot air comprisingan air blast having a temperature of between 300 and 450 F.

5. The process as defined in claim 1, in which said cleaning stepcomprises Washing said segment in an aqueous detergent solution.

6. In the process defined in claim 5 said detergent solution being analkaline solution.

References Cited UNITED STATES PATENTS MORRIS O. WOLK, Primary ExaminerJ. T. ZATARGA, Assistant Examiner US. Cl. X.R.

